Steam rock-drill



(No Model.)

L. B. STONE.

STEAM ROGKDRILL.

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Nrte STATES.

LAVSON B. STONE, OF MARBLEHEAD, MASSACHUSETTS.

STEAM ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 248,896., dated November 1, 1881.

Application tiled August 1, 1881.

To all whom it may concern Be it known that I, Lawson B. STONE, of Marblehead, Essex county, State of Massachusetts, have invented au Improvement in Steam Rock-Drills, of which the following description, in connection with the accompanying drawings, is a specification.

My invention relates to rock-drills; and it consists iu certain improvements whereby the construction ofthe parts is made simpler, more durable, and less expensive, and the operation is more pert'ect` therel being no dead-points.

In the followingdescription thetermdown stroke77 will mean the stroke toward the rock, and upstroke away from the rock, and the words upper7 and under will be used asif the drill were acting' upon the rock vertically beneath it, although itis to be understood that the drill can be set to bore in any desired direction.

The workilig-cylinderis contained in an outer casing, into which the act-uating-iuidis admitted near its lower end when it tlrst acts upon the under surl'ace ot' the piston to produce its upward stroke, and the said cylinder is provided with ports connecting the space above and below the piston, and controlled by a cut-ott' valve that is properly actuated bythe piston and projections upon the pistou-rod to open the said ports when the piston and drill has uearlylinished its upward stroke,thus permitting the lluid to act also upon the upper surface of the piston, which is of larger area than the under surface, so that the piston is forced down by the pressure due to the dili'erence in these areas, and when near the end ot' its downstroke carries the cutfoft valve to close the ports, and thus remove the live-1luid press ure from the upper side otl the piston to permit it to make its next upstroke. A pin that passes through the pistony and a portion ot' the piston-rod is arranged to cause the latter to rotate as usual in making its stroke, and acts as an exhaust-valve for the space within the cylinder above the piston, it permitting the escape of the actuating-fluid from the said space when the drill has completed its downstroke. These elements are found in the drill patented to J. B. Johnson, No. 213,663, March 25, 1879, upon which the present invention is intended as an improvement. In the present invention (No model.)

l the workingcylinder is xed in the outer casing, and fed therewith to advance the drill into the rock by feeding mechanism ot' any usual and suitable construction. The pistonrod passes out through a stuflng-box in the .lower head of the case, through which steam is admitted by a suitable inlet-passage, an annular recess being formed above the lower head ot the case, between the sides ot' the said case and the gland of the stufling-box surrounding the piston-rod.

An annular block, which is herein denominated a cushion or auxiliary piston,'since under-some circumstances it acts as a piston to move the piston-rod, is longitudinally movable within the case in and out from the said annular recess above the inlet-port, in which it has a working lit. An annular shoulder upon the piston-rod lits within this auxiliary head when the rod is at the end ot' its downstrokc, and it' the drill be in a vertical position the auxiliary piston will drop into the aunular recess, and with the piston-rod and its said shoulder will till the entire outer casing, so that when steam is admitted it will act upon the under surface ot' the said auxiliary piston and shoulder to raise them andthe piston-rod making the beginning of the upstroke.

An annular lug at the upper end of the shoulder ou the piston-rod is engaged by the upper end ofthe auxiliary pistou, causing the said rod to move positively therewith until the said auxiliary piston is stopped by engaging with the lower end of the cylinder, when the steam acting upon the annular shoulder causes the piston-rod to continue its upstroke until the shoulder has passed from within the auxiliary pistou, leaving the space previously occupied by it t'ree for the passage ofthe actuating-fluid to reach the under side of the piston which the annular lug on the piston-rod, which may be called the Lvalve-actuating lug,7 engages the cut-off valve and movesit above the lower openings of the connecting-ports ofthe cylinder, permitting the fluid to pass through the ports and act upon the upper surface ot' the piston.

The exhaust pin or valve is made tubular or provided with a longitudinal passage communicating with au exhaust-chamber below the proper, causing it to nish its upstroke, during IOO upper head of the casing, from which the exhaust-steam may be led in any desired direction, and is provided with ports lending into the cylinder and properly located to be uncovered by the pistou when it has completed its downstroke, during which the under side of the pistou has acted upon the cut-offl valve to close the connecting-ports before the said exhaust-ports are open, so that a passage will not be a'orded for the inlet-port through the said connecting and exhaust ports into the said exhaust-chamber to permit the steam to blow through without operating the drill.

Should the drill in its downstroke fail to meet with the rock or other obstructions, the pistou will travel with its momentum until the annular shoulder upon the rod enters the auxiliary piston, it being meanwhile cushioning upon the actuating-duid, which always acts upon its lower surface, and should it go far enough the annular lug above the said shoulder will engage the auxiliary pistou and carry it into the annular recess at the lower end ot' the case, where it will be brought to rest by the cushioning action of'the uid upon its large area without shock to the lower head of the case.

A stop-ring is interposed between the cutotfvalve and the upper surface ofthe auxiliary pistou, which, in case ot' such excessive stroke or overshot ot' the drill, will prevent the said cut-O` valve from passing beyond and uncovering the connecting-ports before the shoulder has entered the auxiliary piston and closed the casing to prevent the uid from reaching the cylinder at all; and iu the upstrokc the said stop-ring and auxiliary piston will cause the valve to-close the said ports before the said shoulder leaves the auxiliary pistou.

Instead of making the usual large connecting-ports in the cylinder by cor-ing, the external diameter of the cast cylinder is made cousiderably smaller than the internal diameter of the casing, and a thin tube, preferably of steel, fitting iu the said casing, is placed over the cylinder, forming the outside thereof', au annular space thus being left between the said tube and cast portion of the. cylinder to form a continuous passage for the actuatingfluid, into which a sucient number of small port-openings are made in the proper position near either end of the cylinder, such openings forming less obstruction to the movement of the cut-oli' valve than the larger portopenings shown in the former patent referred to. The valve is made to fit between the cylinder so closely as to remain held by its friction in any position until positively moved therefrom, and consists of a main portion cut longitudinally and chambered upon its inside to receive an elastic tube set with a tendency to spring outward and press the main portion against the inside of the cylinder, it also covering the saw-cuts in the main portion, which receives the positive blows of the piston and actuating-lug upon the piston-rod.

Figure l is a longitudinal section of the drill constructed iu accordance with this invention, the piston being at the end of its downstroke;

Fig. 2, a transverse section on line Fig. 1;

Fig. 3, a transverse section on line y, Fig. 1; Fig. 4, a partial section, showing the relative position of the ports when the piston is in its lowest position as before the actuating-fluid is admitted; and Fig. 5, a similar partial section, showing the piston near the end of its upstroke, at the point where the fluid is first admitted to produce the downstroke.

The outer casing, @consists ot' a tube or cylinder made smooth outside and inside, and provided at its lower end with a head, b, containing the main inlet-port c, and provided with a stuffing-box,M d, the upper gland or bushing, d', of which extends through the head b iu the 'casing a., thus forming an annular recess, e,

just above the said head. The auxiliary piston or cushionfis made to fit within the said recess e, as shown inFig. 4, and to move longitudinally in the casing a as a cylinder under the pressure of the fluid entering th e port c. the said auxiliary pistou having au upward projectiomff, which enters arecess, g, between the casing a and the lower end of the workingcylinder h, the upper end, h', of which is turned to tit the casing a., while the portion traversed bythe piston t' is iliade ofconsiderably smaller external diameter than the said casing, and receives a tube, h2, fitting tightly upon the ends ot' the said cylinder and of sutliciently large bore to leave a space,j, entirely surrounding the main portion ofthe cylinder to form a connecting port or passage between its upper and lower ends, a series ot' small port-openings, k kf, being made from the inside of the cylinder, at either end thereof, into the said passagej. The lower port-openings, 7c, are controlled by a valve, I, actuated by the under surface, 2, of the piston t' iu its downward movement to close the said openings k, and by the valveactuating lug m upon the piston-rod i in the upward movement thereof to uncover the said port-openings and permit the fluid to pass through the passagej and act upon the upper surface of the piston fe', as shown bythe arrows, Fig. 5.

The main portion of the valve l is divided by two or more longitudinal saw-cuts, as ind-icated in Fig. 3, (the plane of section ot' Fig. l passingthrough them asiudicated by the omission otl the diagonal hatchingsg in order to permit it to expand to press against the inner walls of the cylinder h, so that it will remain i cuts closed. When necessary it may receive IOO IOS

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Masas a covering upon its outer surface-of proper material to work well upon the inner surface of the cylinder h, such a covering being shown at l2, Fig. 4.

The lug m is provided with ports m', to permit the passage of the steam between the piston-rod t' and the valve l when the said lug and valve are in contact, as shown in Fig. 5. l

`The head h ofthe cylinder h is chambered to receive the ratchet-head a of a piu, a', extending down into the cylinder 71 and passing with a piston tit through a bushing, i2, in the piston-1'.. The lower end ot' the said pin is provided with spiral channels 3, engaging wings 'i3 in the piston-rod t" to canse the said rod to rotate in making its upstroke, the ratchet a and pin a being then prevented from rotating by the pawls n2, Fig. 2, in the usual manner. .The said pin a is bored axially atits upper end, or provided with a longitudinal exhaust-passage, 4, into which exhaust-openings 5 lead from the upperendsot` the channels 3, the said openings, when uncovered by the bushing i2 at the end of the downstroke of the piston, permitting the tiuid to escape from the cylinder h, as shown by the arrow, Fig. l, the port-openings k being closed by the valve l before the said openings 5 are uncovered. The ratchet a, connected piu a', and pawls a2 and their springs are heldin place in the head h ot' the cylinder by a t'ollower, 0 which forms an exhaust-chamber, into which the exhausting-fluid is conducted from the passage 4 by a short union or nipple, 5. The exhaust may be led from the said exhaustchamber lthrough any suitable passage, as by the tube p, herein shown as passing through the head b ofthe casing a.

Au annular shoulder, r, upon the pistou-rod t" `uelow the valve-actuating lug m enters the auxiliary piston fit' tbe drill in its downstroke fails to meet the rock or makes abnormally long strokes, owing to the failure ofthe entire machine to be fed forward as fast as the rock is cut, and if the abnormal downward movement or overshot is sufficiently great, .the lug m will engage thc said piston f, causing it to move with the rod fi iu the casing a as a cylinder until the movement is arrested by the tiuid in the recess e.

Astop-ring,s,in thelowerend ofthec) linder It preventsthevalve Zfrom being thrown below the openings k before the shoulder r enters the pistonf, and thus prevents the passage oftluid to the said port-openings, and when the drill is started after having stopped in its lowest position, (shown in Fig. 4,) with the pistonfin the recess e, the stop-ring s, in conjunction with the said pistonj', moves-the valve Z sufieiently to close the-openings cin the beginning ofthe upstroke.

The gland d of the stuffing-box d is made adjustable, as by means of washers in the head b above it, so as to govern the amountofopening for the actuating-Huid between it and the auxiliary piston j', when in the position shown in Fig. l.

The piston-rod t" carries at its lower end the drill-holding chuck, (shown iu Fig.1 in the eX- treme upward position.) It consistsofa tapering portion, t, continuous with the rod, and a corresponding tapering block, t', detached from the portion t, but retained in place thereon by the dowel-pins u a. The said portions 1 t are provided with a socket to receive the drill-bit w, upon which they are tightly wedged by the tapering ring z, which acts by its momentum to tighten the hold of the clamp at every blow ofthe drill.

By the employment of they dowel-pins a a the movable block t will be held in place when the ringe is knocked upward to release the drill instead of dropping out, as occurs in the ordinaryl chuck, which is made without the said pins; but by an extreme upward movement of the ring` z the block t may be removed, as is desirable when, owing to the situation of the machine, it is necessary to remove the drill-bit laterally from the chuck.

The Huid, when entering with the ports in the position shown in Fig-1, first acts upon the auxiliary piston f, and by the lug m and rings raises the piston-rod t" and valve k until the said auxiliary piston is positively stopped by the lower end of the. cylinder, as shown in Fig. l, the valve l then closing the openings k, after which the pistou-rod i, with its momentum and the Huid-pressure on the shoulder r, will continue itsupward movement until the said shoulder has passed ont of the pistonf, when the tluid will pass therewith and act on the under surface, 2, ofthe piston t', causing it to complete its upstroke, during which the projections m will have engaged the valve t and moved it above theopenings k, as shown in Fig. 5, to permit the fluid to pass through the passagej and act on the upper surface of the piston 1'., rst checking its upward movement and then causing it. to make its downstroke. The valve L remains held by its friction above the ports k until engaged by the under surface, 2, of the piston fi a short space in its stroke bei fore the exhaust-openings 5 are uncovered, the stroke being finished to uncover the said openings by the expansion of the fluid above the piston; and for most effective operation the drill should meet the rock as soon as the said exhaust-openings 5 are uncovered.

It will readily be seen that it' a sufcient downstroke is permitted to uncover the said exhaust-openings 5 the drill will operate positively and continuously, it starting from any position in which it. may have been stopped or placed, and operating, without dead-points or any opportunity for the steam to blow through inelfectually.

In its normal and most effective operation the piston in its upstrok-e will nearly reach the top of the cylinder h., it being carried by its momentum above the position shown in Fig. 5, and the machine should be fed fast enough to cause the downstroke to be terminated somewhat above the position shown in Fig. l just before the shoulder 1' enters the auxiliary pistonf.

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I claiml. The outer casing and its head provided with an inlet-port, combined with the pistonrod passing through the said head, and the auxiliary piston working in the saidcasing, and adapted to engage the said piston-rod and lact as a piston therefor during a certain portion ot its stroke, substantially as and for the purpose described.

2. The casing with its head containing the inlet-port, and provided with a stuing-box arranged to form an ann nlar recess above the said head, combined with the auxiliary piston titted to the said recess, and the piston-rod provided with a shoulder fitted to the said piston and operating in conjunction therewith in the said casing as a cylinder, substantially as described.

3. The casing provided with an inlet-port near its lower end, and the Working-cylinder provided with a connecting port or passage from the space below to that above the piston, combined with the piston and the exhaust pin or valve titted therein, the said pin being provided with a longitudinal exhaust-passage leading through the cylinder-head, substantially as described.

4. The herein-described valve, consisting of a main tubular portieri divided longitudinally and counterbored or chainbered internally, combined with a spring-ring located in the said chamber, to press the said parts outward against the containing-cylinder, and adapted to cover the lines of division of the main portion ot' the valve, substantially as described.

5. The herein-described workingcylinder, it consisting ot'a main cast portion properly bored internally, and a tubularjacket surrounding it and inclosing a space upon the outside of the main bored portion, which is provided with series of small portopenings passing from its interior into the said space, substantially as and for the purpose described.

6. In a rock-drill, the combination, with the reciprocating piston-rod, of the chuck consisting ofa halt-round tapering portion continuous with the said rod, and a corresponding half-round tapering movable block, and an internally-tapering ringadapted by its longitudinal movement to wedge the said portions together upon the drill-bit,com'bined with dowelpins to hold the said fixed and movable portions together and prevent the. latterfrom dropping when loosened to release the drill-bit, substantially' as described.

7. The outercasing and working-cylinder therein, provided with a port and a lrictionally-held valve to control it, and a piston and a piston-rod to actuate'the said valve, combined with the auxiliary piston for the said pistonrod working in the said casing, and the stopring interposed between the said valve and auxiliary piston, and co-operating with the latter to control the valve, substantially as and for the purpose described.

8. In a rock-drill, the cylinder consisting ot' an inner and outer tube, having an annular space inclosed between them, and provided with series of port-openings near either end thereof, connecting the said space with the lnterior of the cylinder, combined with a valve to control one ot' the said series ot` openings, and the piston, piston-rod, and valve-actuating lug thereon, arranged and to operate substantially as and for the purpose described.

In testimony whereot'l have signed my name to this specification in the presence ot' two subscribing witnesses.

LAWSON B. STONE.

Witnesses:

Jos. P. LIVERMORE, W. H. SlGsToN. 

